The present invention relates to an apparatus and a method for recognizing a three-dimensional shape of an object by means of camera systems. More particularly, the present invention is concerned with a system for recognizing the three-dimensional shape of an object, which system is advantageously suited to application for inputting graphics data to a computer graphics system.
According to a hitherto known method of recognizing a three-dimensional shape (3D shape) of an object, images of the object of concern are picked up by television cameras from a plurality of different points of vision (sight), wherein the three-dimensional shape of the object is reconstructed in a three-dimensional coordinate system within a computer in the form of a voxel model by adopting a so-called cone-silhouetting method. Reference may be made, for example, to "Computer Vision Study Report 37-2 (1985)" of The Information Processing Society of Japan. However, the shape obtained by this known method consists only of a set of enveloping surfaces of the object, and no consideration is paid to such shape which has local concaves.
On the other hand, a method capable of recognizing and inputting the local concave portions to a computer is known as a binocular three-dimensional vision method, as is disclosed in "Collection of Lectures in 24-th SICE Assembly", p.p. 847 to 848 (1985).
The prior art method relying on the cone-silhouetting method according to which the three-dimensional shape is reconstructed from information of contour lines of images of an object is disadvantageous in that when local concave portions which do not make appearance in the form of contour lines are present in the object can not be recognized, the shape data inputted to the computer is correspondingly degraded in respect to the accuracy.
On the other hand, in the case of the shape recognition method based on the binocular three-dimensional vision method suffers a problem that when the binocular parallax (distance between points of vision) is enlarged with a view to assure an adequate accuracy, difficulty is then encountered in determining or establishing correspondence relations between left and right images, making thus the solution inaccurate by contraries.